DOCSIS®
Rev. A00
Agenda
Items for discussion

DOCSIS/EuroDOCSIS


Overview of Standards, Features &
Benefits
DOCSIS 3.0/EuroDOCSIS 3.0

CATV Market Dynamics

New Technical Directions & Features

Network Preparation
DOCSIS®
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DOCISIS
DOCSIS 3.0
2
DOCSIS Review
Overview, Features & Benefits
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DOCSIS
An Overview

DOCSIS system


DOCSIS specification


Enables transparent bi-directional of Internet Protocol (IP) traffic, between the cable system headend and
customer location
Defines PHY & MAC layer protocols for communication & Ethernet frame transport between CMTS & CM
DOCSIS network comprises:

Cable Modem Termination System (CMTS) located at the headend

Cable Network - an all-coaxial or hybrid-fiber/coax (HFC) cable network

Cable Modem (CM) located at the Customer Premise
Transparent IP traffic
Wide Area
Network
Cable Network
(HFC)
CMTS
Cable Modem
CM/CPE
Interface
CMTS/WAN
Interface
DOCSIS®
CPE
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DOCSIS
Milestones
DOCSIS 1.0 (1999)
• 1st products certified (CableLabs started project in 1996)
• Open standard for high-speed data over cable
• Modest security, Best-effort service
DOCSIS 1.1 (2000)
• Quality-of-Service (QoS) service flows
• Baseline Privacy Interface (BPI+) Certificates
• Improved privacy & encryption process
DOCSIS 2.0 (2002)
• Improved throughput & robustness on Upstream
• 64/128 QAM modulation & higher symbol rates with FEC
• Programmable interleaving to upstream channels
DOCSIS 3.0 (2006)
• Channel bonding (4U/4D) for increased capacity
• IPv6 support
• Improved security (AES)
DOCSIS®
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DOCSIS
HFC Spectrum Allocation

The frequency spectrum used in an HFC network is split into two parts:

Downstream spectrum which delivers services from the headend to the end user

Upstream spectrum for sending traffic from the end user to the operator
Europe
FM
Analog Video
PAL
EuroDOCSIS
US
5MHz
65 80 87
108
Downstream
North America
FM
Analog Video
NTSC
US DOCSIS
US
42
Upstream
DOCSIS®
EuroDOCSIS
DS
862MHz
Upstream
5MHz
Digital Video
MPEG/DVB + VOD
80 87
Digital Video
MPEG/DVB + VOD
108
US DOCSIS
DS
862MHz
Downstream
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DOCSIS
Upstream Physical Layer

The DOCSIS Specification defines Modulation and Coding Schemes outlined in
the following table for the Upstream
DOCSIS®
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DOCSIS
Downstream Physical Layer

The DOCSIS Specification defines Modulation and Coding Schemes outlined in
the following table for the Downstream
DOCSIS®
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DOCSIS
Power Ranging


Ranging is used to synchronize CMs and align them with the CMTS

TDMA requires coarse alignment (±800 nsec)

S-CDMA requires accurate alignment (±1 nsec)

CM sends a RNG-REQ message

CMTS responds with a RNG-RSP message

Contains Timing Adjust (Resolution = 0.3815 nsec)

also Power adjust, Frequency adjust, Pre-EQ parameters
Ranging is a two-step process:

Initial maintenance (coarse time alignment)

Periodic station maintenance (fine time alignment)
DOCSIS®
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DOCSIS
CM Protocol Stack

DOCSIS MAC

Forms part of the data link layer that supports topology dependent functions

Uses services of the Physical Layer to provide services to the Logical Link Control (LLC)

In the OSI 7-layer model, the Media Access Control is a part of layer 2, the data link layer.
DOCSIS®
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DOCSIS
Media Access Control (MAC)


Media Access Control (MAC) Sub-Layer

Controls access to the Physical Layer (the channel)

Allows multiple users to share a communications channel

Separate physical channels (upstream/downstream) controlled by the CMTS

No direct peer-to-peer (CM-to-CM) communication
Downstream MAC

Only one transmitter (CMTS) and multiple receivers (CMs)

Quality of Service (QoS) can be assured by:


Token bucket rate limiting, Reserved data rates, Traffic Priority
Upstream MAC

Multiple transmitters (CM) with One receiver (CMTS)

The CMTS arbitrates access to the channel

Each upstream channel is described in mini-slots

MAP messages are broadcast downstream to describe which CM can transmit and when

Access Control is Reservation based
DOCSIS®
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DOCSIS
DHCP Server & Process


DHCP Server

Assigns IP addresses to client computers

Addresses are “leased” to clients (Cable Modems or CPEs) for a period of time

IP addresses can be reserved for specific clients or assigned from “pools”

Clients may be authenticated based on their MAC address

Address may be assigned from different “pools” based on extended options
DHCP Process

The DHCP server requests the following parameters from the Cable Modem (CM):

IP address of the CM

IP address of the TFTP Server (for DOCSIS Configuration file)

IP address of the DHCP Relay Agent (if DCHP server resides on a different network)

TFTP/DOCSIS Configuration file name

Subnet Mask to be used by the CM

Default IP Gateway

Time of Day Server and SYSLOG Server IP address
DOCSIS®
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DOCSIS
Time of Day (TOD) Server

Time of Day (ToD) Server

Internet Time Protocol (ITP) per RFC 868

UDP and TCP requests honored on port 37

32-bit value defining the number of seconds since 00:00 (midnight January 1, 1900 GMT)
DOCSIS®
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DOCSIS
TFTP Server

TFTP (Trivial File Transfer Protocol) Server




The following settings are mandatory in the TFTP configuration file:



In accordance with RFC 1350
UDP port 69
Small and easy to implement with read and write to and from remote servers
Network Access Configuration Setting
Class of Service Configuration Setting
The following settings are optional:








Downstream Frequency
Upstream Channel ID
Vendor ID
Baseline Privacy
SNMP Write-Access Control, SNMP MIB Object & SNMP IP Address (if applicable)
Software Server IP Address
CPE Ethernet MAC Address
Vendor-Specific Configuration (if applicable)
DOCSIS®
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DOCSIS 3.0
CATV Market Dynamics
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DOCSIS 3.0
Business Drivers

Support new high bandwidth services of 50 to 100Mbps

Migrate existing customers to higher tier services

Better and more robust data encryption

Provide more IP address space using IPv6

Limit and reduce node splits

Reduce overall cost of CMTS ports

Independent scalability of upstream & downstream
DOCSIS®
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DOCSIS 3.0
Higher Bandwidth Applications
Web 2.0
Digital
Photos
Home
Networks
Data &
VoIP
Gaming
MP3
WMV
VOD
DVR/PVR
DVD
Blu-ray
You Tube
SDTV
HDTV
DOCSIS®
Mobile
Video
iPod
Walkman
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DOCSIS 3.0
Consumers greed for speed
DOCSIS®
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DOCSIS 3.0
Services driving Channel Bonding



High bandwidth residential data and content

Video and photo uploads

Proliferation of social networking sites and applications
IP Video over DOCSIS (VDOC)

High definition Video to multiple devices

PCs, hybrid STBs, portable devices

High bandwidth Internet streaming
High Bandwidth Video conferencing


Cisco TelePresence
Commercial service

High bandwidth symmetrical data services

Bonded E1/T1 circuit emulation

High bandwidth Ethernet / L2VPN services
DOCSIS®
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DOCSIS 3.0
New Technical Directions & Features
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DOCSIS 3.0
Major Feature Overview
Increased DS bandwidth
• Bonded Downstream Channels
• 56Mbps (RAW) each, 448Mbps Total
Increased US bandwidth
• Bonded Upstream Channels
• 27Mbps (RAW) each, 122Mbps Total
IPv6
• IPV6 allows for 3.4x1038 IP addresses
• IP addresses are lengthened from 32 bits to 128 bits
Backwards compatibility
• Existing DOCSIS 1.0, 1.1 and 2.0 systems
• Scalable deployment with easy subscriber migration
IP Multicast
• IPTV-type applications
• Efficient “switched-video-like” bandwidth usage
Commercial
• E1 & T1 circuit emulation
Network Security
DOCSIS®
• Early Authentication and Encryption (EAE) and AES
128bit encryption which is more robust and secure
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DOCSIS 3.0
Channel Bonding

Channel bonding basically means data is transmitted to/from Cable Modems
using multiple individual RF channels instead of a single channel
Using DOCSIS 3.0, data is transmitted to cable modems using
multiple channels
DOCSIS®
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DOCSIS 3.0
Throughput Compared
Date Rates – Annex A
DOCSIS Version
DOCSIS®
Downstream
Upstream
1.1
~ 55.62 (50) Mbps
10.29 (9) Mbps
2.0
~ 55.62 (50) Mbps
30.72 (27) Mbps
3.0 (4 Channels)
~ 222.48 (200+) Mbps
122.88 (108+) Mbps
3.0 (8 Channels)
~ 444.96 (400+) Mbps
122.88 (108+) Mbps
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DOCSIS 3.0
Upstream PHY Modes


Advanced Time Division Multiple Access (A-TDMA)

Used widely in DOCSIS 2.0 and DOCSIS 1.1 systems

CMs transmit one at a time, occupying the entire upstream channel during transmission

Transmissions consist of a preamble, data burst, and guard time

Better immunity to narrowband interferers and generally performs better above 15 MHz
Synchronous Code Division Multiple Access (S-CDMA)

Applicable to DOCSIS 2.0/3.0 systems only

Multiple CMs able to transmit simultaneously with shorter preamble and no guard times

Better immunity to burst noise and performance below 15 MHz
5MHz
DOCSIS®
42MHz or 65MHz
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DOCSIS 3.0
Downstream Channel Bonding


Cable Modem Termination System (CMTS)

A downstream packet stream or flow is distributed to a set of
channels called the Downstream Bonding Group (DBG)

Bonded packets are marked with a sequence #

A Downstream Service ID (DSID) identifies a stream of packets
Cable Modem (CM)

Bonded packets can arrive out of order

Bonded packets are “re-sequenced” using the sequence #

The DSID is used re-sequence each flow or group of flows
independently
DOCSIS®
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DOCSIS 3.0
Upstream Channel Bonding

Upstream Bonding

Packet Striping of a minimum of 4 channels

Delivers in excess of 50 Mbps

Single flow can consume entire bandwidth on multiple Upstream Channels

Implements Continuous Concatenation & Fragmentation (CCF)

Improved form of concatenation and fragmentation needed for DOCSIS 3.0 operation
US1
Request 1000 bytes
CMTS
Grant 200
US2
P4
P3
P2
P1
Grant 300 bytes
U3
Grant 500 bytes
DOCSIS®
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Cable
Modem
26
DOCSIS 3.0
Upstream Requests and Grants

Cable Modem (CM)


When a CM is ready to transmit data, it randomly selects a Request contention interval
among all upstream channels

Transmits a 7-byte REQ message to the CMTS, which identifies the CM (from the
Service ID) and specifies the number of bytes in queue

Retransmits the request, if there is no response from the CMTS
Cable Modem Termination System (CMTS)

Queues and prioritizes the incoming REQs

Selects an upstream channel and reserves future mini-slots for the requesting CMs

An individual request can be split into multiple “grants” on different channels

Communicates the grants to the CMs via MAP messages
DOCSIS®
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DOCSIS 3.0
MAC Domain

MAC Domain

Defined as a sub-component of the CMTS

Controls all DOCSIS functions on a set of downstream and upstream channels

Contains at least one DS channel and one US channel

Provides layer 2 data forwarding services between the CMTS and all the CMs registered
to that particular MAC domain

Implements all DOCSIS MAC management message exchanges with CMs across multiple
US & DS channels using a common MAC address

Implements load balancing of CMs and bandwidth of channels
DOCSIS®
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DOCSIS 3.0
New MAC Functions

MDD Descriptor


Plant Topology



Describes fiber nodes and how they
are split/combined
Ambiguity Resolution


Describes Plant topology
Downstream Bonding Group (DBG)
Upstream/Downstream bonding

Sequencing for packet flows

Dynamic Bonding Change (DBC)

Bonding group attributes (low latency)
CM status report

Reports CM condition
DOCSIS®

CM Control report

Used to force actions such as reboot,
or channel muting.
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DOCSIS 3.0
New MAC Management Messages (partial list)
Message
Description
MDD
MAC Domain Descriptor
B-INIT-RNG-REQ
Bonded Initial Ranging Request
DBC-REQ
Dynamic Bonding Change Request
DBC-RSP
Dynamic Bonding Change Response
DBC-ACK
Dynamic Bonding Change Acknowledge
DPV-REQ
DOCSIS Path Verification Request
DPV-RSP
DOCSIS Path Verification Response
CM-STATUS
Cable Modem Status Report
CM-CTRL
Cable Modem Control
REG-REQ-MP
Multipart Registration Request
DOCSIS®
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DOCSIS 3.0
CM Provisioning

During initialization, the CM downloads a configuration file from the cable operator

The Config file defines:

Quality of Service (QoS) parameters


Filters



Priority, rate limiting, bandwidth guarantees, etc.
block Windows file sharing (netBIOS, SMB, CIFS)
Privacy (encryption) parameters
The CM then sends a Registration Request message to the CMTS containing the
QoS parameters
DOCSIS®
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DOCSIS 3.0
Cable Modem Registration
Scan digital channels & acquire QAM/FEC/MPEG
lock of DOCSIS DS & DOCSIS PID
SYNC, UCD, MAP messages
MDD message
Receive MAC Domain Descriptor (MDD) Message
CMTS
Tune additional downstream frequencies to
determine service group
Cable
Modem
B-INIT-RNG-REQ message
Authentication & Key Exchange
DHCP DISCOVER packet
DHCP OFFER packet
Select upstream channel listed in MDD
Find Initial Maintenance interval in MAP messages
Send RNG-REQ, receive RNG-RSP, adjust Txmitter
Transition to ranging station maintenance
Establish IPv4 or IPv6 communication via DHCP
DHCP REQUEST packet
DHCP RESPONSE packet
TOD Request/Response messages
TFTP Request/Response messages
REG-REQ message
Download Configuration File (TFTP)
Send REG-REQ, receive REG-RSP, send REG-ACK
REG-RSP message
REG-ACK message
Provides Rx-Chan(s)
Receive Rx-Chan(s) configuration
BPI+ initialization if configured
DOCSIS®
Confirm all Rx Channels
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DOCSIS 3.0
Better Network Security

Secure provisioning prevents unauthorized CMs from accessing the network


Early Authentication and Encryption (EAE)

Provides enhanced security

Authenticates CM after power ranging and before DHCP process

Signaling occurs in the MDD message (TLV 6)

Enabled on either a per CM or per MAC domain basis
CMTS Proxy Server

CMTS acts as a TFTP server to the CM and as a TFTP client to the provisioning server

Config parameters are enforced since CMTS receives the file first

Provides config file authorization

DHCPv6 authentication

New MIC hash algorithm (MMH)
DOCSIS®
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DOCSIS 3.0
IPv6 in Cable Networks

IPv6 is fundamental feature of DOCSIS 3.0 and provides numerous benefits:






New address size and format - 128 bit vs 32 bit addressing
Smarter packet – simplified provisioning, built-in security, improved mobility, etc.
Restores global connectivity – removes Network Address Translation (NAT)
CM operates in bridging or routing modes
CM management stack operation - IPv4 only, IPv6 only or Dual mode
MDD message contains IP type - conveyed between the CMTS and CM
DOCSIS®
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DOCSIS 3.0
Quick Summary

DOCSIS 3.0 review

Physically the same as DOCSIS 2.0 signals

Consists of multiple QAM signals bonded logically together

Bonded channels can be contiguous or non-contiguous:

Contiguous - consists of frequency consecutive signals

Non-contiguous – interspersed with other carriers

MPEG-2 transport for downstream signals

QAM transport for upstream signals

IPv4 or IPv6 support

Enhanced security using EAE, etc.
DOCSIS®
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DOCSIS 3.0
Network Preparation
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DOCSIS 3.0
Basic steps for being prepared
RF
Bandwidth
Availability
DOCSIS®
Headend
and Core
Network
Equipment
Preparation
Verify
QAM64
Upstream
Txmission
Verify
QAM256
Downstream
Txmission
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DOCSIS 3.0
Modem
Emulation
IP/Ethernet
Testing
(Ping, FTP,
RFC2544,
Web)
37
DOCSIS 3.0
Where can more RF bandwidth come from?
Expand the plant
to 1GHz
Digital only
systems
Use unusable
old analog
broadcast
channels
Digital Simulcast
migrating
selected analog
channels
Node Splits
DOCSIS 3.0
Switched Digital
Video for SD &
HD content
DOCSIS®
requires a minimum
of 4 to 16
downstream
channels
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CMs are able to
receive 4 DS
channels spread
across a 60MHz
window
38
DOCSIS 3.0
Bandwidth Management

Reclaim Analog bandwidth for more digital spectrum


Node splits


Transmit only the content being actively watched
Efficient channel use


Reduce the homes passed per HFC node, reducing contention/home for Unicast services
Switched Digital Video (SDV)


More QAM channels for Digital Broadcast, VoD, SDV and DOCSIS
Manage channel lineup, fill the gaps, and mitigate noise to utilize available spectrum
1GHz upgrade

Make new spectrum for new CPE above 860 MHz
Soon 1GHz
Today 870MHz
DOCSIS®
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DOCSIS 3.0
How much can we gain with spectrum changes?
Extending the US band from 65 MHz to 85 MHz
250 Mbps
• New DOCSIS technology becoming available
• FM band is compromised
• Large network investment required
Creating an upstream band 900 to 1000 MHz
•
•
•
•
Adaptation of DOCSIS (RF up converter)
Ingress noise issue “mostly solved”
862 to 1000 GHz considered an extension of DS band
Huge investment in diplex filters and return amplifiers
New upstream band above 1000 MHz
•
•
•
•
500 Mbps
1000 Mbps
Adaptation of DOCSIS (RF up-converter)
Ingress noise issue solved
Quality concern regarding passives and cables
Investment in diplex filters and return amplifiers
DOCSIS®
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Acknowledgements
Information Sources
DOCSIS®
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Acronyms/Abbreviations
Common terms in DOCSIS systems
DOCSIS®
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Thank you.
Any questions?
DOCSIS®
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